Syncing digital media to performances in music concert settings is not a new practice. Sync methods have been developed in the club scene, the classical concert hall and other music venue types. Existing sync methods generally fall into the following categories:                1. Scrubbing. Scrubbing is a well-known audiovisual editing technique that allows an individual to increase or decrease playback rates of digital files. Scrubbing is most often accomplished manually as a way to achieve a rough, imprecise sync so no particular consideration is given to matching rhythmic cue points. As a result this approach is not well suited to produce a full and careful sync.        2. Beat Matching. Beat matching is a method that has been used in dance clubs by disk and video “jockeys” for many years. This method could be described as a more sophisticated form of scrubbing where the digital media to be synced is mapped to the beat or pulse of a second media file. In this method playback of the first media file is stretched or condensed to sync the downbeats of the two media files in an attempt to seamlessly blend the tempo of the two. The drawbacks to this method are that one needs to pre-set the beat sync before the live performance since there is no completely efficient way to accomplish this function in real time. This method assumes that tempo of the video will remain unchanged, with the operator adjusting the playback rate of the audio files to match the video.        3. Click Tracks Click tracks have been used in soundtrack recording sessions for many years and have more recently been adapted for use in live concert performances. The “click” is an audio metronome embedded in the media file to be synced. The “click” is fed through earpieces to the musicians who essentially play along to the tempo they hear. The audience never hears the “click” and so long as the musicians stay “on the click” the sync between digital file and live performance will be perfect.        4. Video Chapters. During the editing process the video file is divided into chapters with new chapters beginning at assigned cue points in a musical score. When the live performance reaches a cue point the video file is advanced to the next chapter, either manually or by a computer process designed to identify the cue points through pitch recognition or some other score reading technique. Video chapters have also been used to sync movie files to music.        
In each category above, the sync achieved is either very imprecise and or it requires pre-recorded music with a perfectly steady beat such as computer generated “techno” music. Also, none of the foregoing methods are satisfactory in the situation where a live performance of a piece of music, a play, a dance or the like is to be precisely synced with a digital media file. The problem stems from the fact that no two live performances of the same piece are the same due to inherent tempo variations that occur, and this result holds true even if performed by the same individuals. These tempo variations occur because human beings are not capable physiologically of performing with the millisecond precision of a digital timing device, and due to the fact that artists will purposefully and for artistic effect increase or lower the tempo of a particular section of the live performance. However, a pre-recorded audio or video track is an invariable replica of one particular performance with all of its particular intrinsic tempo variations. As a result, pre-recorded audio or visual tracks will invariably become out of sync with live performances as a joint performance thereof proceeds.
What is missing is a system that provides for a way of syncing a live performance with all of its inherent variability with a static digital video file. However, each existing method described above fails because the approach focuses on trying to match the live performance to the invariable recorded work, and generally lacks in precision, flexibility, artistry or a combination of thereof. Thus, prior art syncing techniques fail to provide for the needed fluidity, flexibility and accuracy required for transitions from one tempo to the next and/or from one musical section to the next. Prior art syncing techniques can allow for some rate variations, but only where they are very small, and/or very infrequent or also require that the tempo is set or determined by the recorded media, not the live performance.